Answer:
0.41
Explanation:
given,
mass of the car, m = 2290 Kg
initial speed = 10.5 m/s
mass of another car, M = 2780 Kg
distance moved = 2.80 m
coefficient of friction = ?
conservation of energy
m u = (M + m) V
2290 x 10.5 = (2290 + 2780) V
V = 4.74 m/s
using equation of motion
v² = u² + 2 a s
4.74² = 2 x a x 2.8
a = 4.02 m/s²
now using equation
a = μ g
4.02 = μ x 9.8
μ = 0.41
Input heat, Qin = 4 x 10⁵ J
Output heat, Qout = 3.5 x 10⁵ J
From the first Law of thermodynamics, obtain useful work performed as
W = Qin - Qout
= 0.5 x 10⁵ J
By definition, the efficiency is
η = W/Qin
= 100*(0.5 x 10⁵/4 x 10⁵)
= 12.5%
Answer: The efficiency is 12.5%
I like fortnite too:):):)
